In recent years, three-dimensional image display apparatuses not requiring special glasses are being developed. For example, some integral-imaging 3D image display apparatuses have been developed, in which images taken in plural directions are shown according to the viewing angles to provide a stereoscopic image. The integral-imaging system has a plurality of parallax images and therefore provides motion parallax, in which the image seen by a viewer changes as the viewing point of the viewer moves.
Each integral-imaging 3D image display apparatus is manufactured by bonding a lenticular lens to a planer display substrate such as a liquid crystal panel (hereinafter, referred to as a cell substrate). The influence of defects caused in the cell substrate on each parallax image of the stereoscopic image can be checked by a lighting test which displays an image after the lenticular lens is bonded to the cell substrate.
However, according to such a method of observing each parallax image with the cell substrate being bonded to the lenticular lens, it is not known how each parallax image looks when the cell substrate is defective until the cell substrate is bonded to the lenticular lens. If the cell substrate is defective, the lenticular lens needs to be separated from the cell substrate. In many integral imaging 3D image display apparatuses, the cell substrate and lenticular lens are bonded to each other with an adhesive. Accordingly, it is difficult or impossible to separate the lenticular lens from the cell substrate. If the lenticular lens cannot be separated, the cell substrate and lenticular lens are both disposed of.
Even if the lenticular lens can be separated from the cell substrate, it requires time and good skills to separate the lenticular lens, which is made of a glass component in many cases, from the cell substrate without scratching the same. Accordingly, the method of inspecting a cell substrate for defects after bonding the lenticular lens to the cell substrate requires high manufacturing cost and long manufacturing time.